EP publication No. 0,380,448 discloses a seed pellet comprising a coated seed, where the coating for instance is made of vermiculite, binder, water-absorbing material and additives pressed together about the seed on a pelleting press. The seed pellet is intended to be sowed directly in the field, and nothing is stated about the seed pellet being placed in a small pocket in actual germinating units, neither in separate germinating units nor in germinating units in seed or plant tapes.
EP publication No. 0,260,106 discloses a plant growth medium prepared by mixing vermiculite, perlite and a gel-forming material in water and mixing said mixture with plant nutrients. The mixture is dried and shaped into sheets, pellets, granules or the like comprising seeds. No water-absorbing material is used, and it is not a question of inserting the mixture in pockets in the germinating units either. Being without the water-absorbing material it is no longer certain that sufficient moisture and simultaneously sufficient air exist about the roots of the plant.
EP publication No. 0,373,348 discloses a growth medium for plants. This growth medium comprises for instance a filler, such as vermiculite, perlite and the like together with charcoal or activated carbon plus polyacrylamide (SAP) plus possibly peat moss. The prepared medium does not, however, comprise a binder which can ensure that the polyacrylamide is uniformly distributed in said medium by being adhered to the filler.
None of the above mixtures have a completely satisfying effect in the above germinating units.